Expert: Dan Griffin - 1/3/2008

Question
I am in need of help in figuring how to safely raise a 2 car garage in the mountains. I want to pour a concrete pad under the garage then set the footprint on top of the concrete. Right now the floor is dirt and it is on 8 6"x6" concrete footers which is raising it 4" from the ground so you are able to look under the wall and see the outside. I want to turn it into a hunting cabin and need to support and level the garage. The footers have sunk into the ground leaving the garage off level.
I would like to see if anyone has any good ideas for me, I am very handi but have not done this before and I am just a bit concerned about doing it right. I want to make sure I reinforce the concrete at the exterior to support the walls so the concrete won't crack.

Thanks

Answer
Leigh,
You have quite a project.  It would probably help quite a bit to know how big this thing is and how many doors are in it now, and how many doors you intend to keep.  What is it made of now?  Can you see the studs on the inside now?  What is the outside now?  Is the bottom plate still sound?  What is it (2x, timber)?  Is there some particular reason to not take the thing apart, form and pour a proper footing, and build a cabin?  Raising this thing is dangerous and if you are working alone, I'm sure you will be working sporadically which leaves this thing suspended for unknown time frames with unknown weather issues.  Is there enough space to skid this thing elsewhere, pour the footings and concrete and skid it back onto the concrete?  Can you perform the concrete and skid this thing onto it?

To have adequate hold of this thing when you are finished it should have a footing that goes below frost line where this is.  Frost line varies according to location and winter temperatures.  YOu obviously don't have good stable soil now as the building settled.

When you are finished, you want to have a frieze board, sheathing, siding, or flashing that extends down past the top of floor.  There should be 6 inches of concrete showing below this exterior finish above exterior grade.  The ground should fall at least 6" farther down hill in the first 10 feet.  This is to move rain water and snow melt away from the building and footing.

Do you plan to have plumbing in this thing when your are finished? This will have to be dealt with before concrete.  

YOu have left me with so many unknowns  I am about lost on giving you information.  Think about some of this:  you can bolt 2 2x12 on the outside of the building to get out past  the dimension that you need to set concrete forms.  Through bolt several large, as in 6x6x3/8 angle iron clips to the 2x12 about every 4 feet or so on the two longest walls.  Brace across the interior to pull these outside wall lines parallel at the proper dimension.  Use a hydraulic jack or a bunch of them under the angle iron plates to start raising one side.  YOu will need massive quantities of cribbing.  Raise each about 2" to be able to slide in a piece of 2x.  Make absolutely certain that your cribbing stacks are wide set and stable.  start to raise the opposite side.  YOu will soon have a feeling for the raising issues.  It is essential to keep things fairly even, but extremely solid.  I would attempt to raise the thing about a 6" to a foot higher than needed.  Timber shore the corners and mid wall as required.  The timber work will need to span outside your concrete work and footing excavation.

Without more information, I am at a loss to tell much more.